Guest TurboSedan Posted March 6, 2005 Report Share Posted March 6, 2005 as the title says. is it possible? what modifications (if any) would be needed to do this? how many liters would that be? 3.0? i would love to build up a big bore/short stroke 660 this summer Quote Link to comment Share on other sites More sharing options...
Aaron Posted March 6, 2005 Report Share Posted March 6, 2005 A 2.8 crankshaft in a 3400 should make it about a 3.1L. Why? Quote Link to comment Share on other sites More sharing options...
maybe2fast Posted March 6, 2005 Report Share Posted March 6, 2005 what would be the benefit? just the strength of the 2.8 crank? Quote Link to comment Share on other sites More sharing options...
cutlsp Posted March 6, 2005 Report Share Posted March 6, 2005 short stroke quicker revs Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 6, 2005 Report Share Posted March 6, 2005 you'd get the bigger bore the 3.4L block has + the shorter stroke for a better rod/stroke ratio, which should make for better high RPM power and higher redline. as an example, think about the '69 Camaro 302ci smallblock. it was a 327 block with a 283 crank. sure the 302 was made to stay within the 305ci limit, but it was a damn good engine nonetheless. Quote Link to comment Share on other sites More sharing options...
Brian P Posted March 7, 2005 Report Share Posted March 7, 2005 your compression ratio would be like 6.shit:1 though. You'd need custom pistons, essentially 2.8 pistons with the diameter and dish of the 3400 pistons. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 7, 2005 Report Share Posted March 7, 2005 your compression ratio would be like 6.shit:1 though. You'd need custom pistons, essentially 2.8 pistons with the diameter and dish of the 3400 pistons. yeah i figured you'd need custom pistons. i meant any modification dealing with fitting the 2.8 crank into the 3400 block. btw the connecting rods could be re-used couldn't they? thanks Quote Link to comment Share on other sites More sharing options...
Canada Posted March 7, 2005 Report Share Posted March 7, 2005 Compression will be the same. Sure, the piston isn't going up as far, but its not going down as far either. The displacement of a 3400 block with a 2.8 crank..... 76 mm stroke 92 mm bore The volume of a cylinder is pi * r^2 * h. 3.14159 * 4.45^2 * 8.4 = 523 cc 523 * 6 = 3138 cc 3100s are 3136 cc oddly enough. Now.....the advantages of using a shorter stroke, is well, mainly a better rod to stroke ratio so you can rev higher (as TurboSedan mentioned). That way, the rod bearing doesn't have to rotate to such an extreme angle on the journal. Which would be good if the motor had a bad rod to stroke ratio. I want to say its 1.76 for a 3400.....but for the life of me I can't find the rod length anywhere. You also gain a slower piston speed. What you need to do is fix the actual weak point of the motor.....the valve train. It’s only rated at 6200 rpm. Take a look at the LQ1.....with its DOHC setup (and still using the pushrod timing chain and gears) can rev to 7k without much trouble. What to actually upgrade? Well........I blame the entire valve train design. Anyone whoever has had the intake manifolds off a 660 and Gen 3 V8 can tell you there is a major difference inbetween a good design and a piss poor design. Why are the pushrods different lengths anyways? Lets say you did upgrade the valve train somehow and now its good for 7k and you did stick the 2.8 crank in there. Wait a second......you don't make any power past 5500 rpm anyways.....mainly due to the stock restrictive ass exhaust manifolds and lack of head flow. So you are stuck shifting at 6k or whatnot for your ideal shift point.......what good did all that work do? About the only thing a 2.8 crank alone will do is allow you to make LESS torque. If someone was to actually go ahead and build a short stroke 660, they best start off with a LQ1, as it can actually rev and make power that high with a proper set of headers. Me, I'm sticking with the 84 mm stroke. Just ask the small block guys to stick a 350 crank into their 400....they won't. Quote Link to comment Share on other sites More sharing options...
Brian P Posted March 7, 2005 Report Share Posted March 7, 2005 Compression will be the same. Sure, the piston isn't going up as far, but its not going down as far either. So you mean to tell me that if I put in a 2.8 crank with 3.1 pistons, the compression won't be lower? There will be more space at TDC. I would like this explained. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 7, 2005 Report Share Posted March 7, 2005 About the only thing a 2.8 crank alone will do is allow you to make LESS torque. would that still hold true for a turbo application? considering 'most' HM-282 gear ratios, i would think that less torque might be a good thing since the transmission gears & FDR multiply torque enough already. it might just help get more traction in 1st or at least 2nd gear and help top-end pull - the best of both worlds. as for the exhaust & intake, obviously i would be using newer 3400 stuff; the only GEN-2 part i'd use is the 2.8 crank. valvetrain modifications to get to 7k? i don't really know.... where the hell are my pizza and buffalo wings dammit. Quote Link to comment Share on other sites More sharing options...
Canada Posted March 7, 2005 Report Share Posted March 7, 2005 Yes, I am an idiot. The volume at BDC is going to be less and the volume at TDC is going to be greater......creating a lesser compression ratio. Not only can it take in less air per cycle, but it gets sqeezed to a lesser volume. Quote Link to comment Share on other sites More sharing options...
Canada Posted March 7, 2005 Report Share Posted March 7, 2005 As far as the actual compression goes? Well.... I need to know the volume at TDC...................I don't. Quote Link to comment Share on other sites More sharing options...
Jamz Posted March 7, 2005 Report Share Posted March 7, 2005 The crank journal was a bitlarger on 2.8 i think . i remember Collin said that on V660 Quote Link to comment Share on other sites More sharing options...
Tru2Chevy Posted March 7, 2005 Report Share Posted March 7, 2005 Just ask the small block guys to stick a 350 crank into their 400....they won't. Some do.....there is a bada$$ 4th gen Camaro here in Jersey with a turbo 377....he runs low 7's There is more than enough aftermarket to support high-reving sbc's to take advantage of the high-spinning 377's. The only reason that I kept the 400 crank in mine is because I don't have the budget for a all out race motor, and since it still has a stock bottom end, I'm prolly gonna be shifting it around 5600-5800 rpm. [/hijack] - Justin Quote Link to comment Share on other sites More sharing options...
Canada Posted March 7, 2005 Report Share Posted March 7, 2005 Exactly.......the only point to going to that level would be if you can afford the high dollar parts need to actually make power at that high of an rpm. Quote Link to comment Share on other sites More sharing options...
JoroCorona Posted March 7, 2005 Report Share Posted March 7, 2005 Whew... LQ1 + Shorter Stroke + T4 (Or larger) Turbo == One wicked DOHC Shit... That thing would rev to 9000 and put down alot of ponies up there... It would prolly hurt its already weak low end torque tho. Quote Link to comment Share on other sites More sharing options...
Canada Posted March 7, 2005 Report Share Posted March 7, 2005 It doesn't have the intake manifolds to rev that high.....the runners are fat, but they are also long. The bottom end won't rev to 9k.... If you are going make a race motor.....do it with something that will actually make power........LS1, 4G63, 2JZ (which amounts to head bolts for an engine build up) come to mind. Quote Link to comment Share on other sites More sharing options...
JoroCorona Posted March 7, 2005 Report Share Posted March 7, 2005 I'm sure it would rev to 9. Cryo treat the Crank, full port job on the entire upper end, nice big fat intake and exhaust valves, and balance EVERYTHING. It would rev to 9000 easy, and still be making power. 4G63 - Too small LS1 - Too pushrod 2JZ - Alright, I agree on this one. 1000 rwhp on a near stock motor is quite impressive. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted March 7, 2005 Report Share Posted March 7, 2005 If you are going make a race motor.....do it with something that will actually make power........LS1, 4G63, 2JZ (which amounts to head bolts for an engine build up) come to mind. well, i was thinking of something that would easily go into a W-body but i see your point. maybe an LS4 would be a good choice to start with. as far as a short stroke 660...yeah sounds like that would be a high dollar project. Quote Link to comment Share on other sites More sharing options...
Canada Posted March 9, 2005 Report Share Posted March 9, 2005 I'm sure it would rev to 9. Cryo treat the Crank, full port job on the entire upper end, nice big fat intake and exhaust valves, and balance EVERYTHING. It would rev to 9000 easy, and still be making power. 4G63 - Too small LS1 - Too pushrod 2JZ - Alright, I agree on this one. 1000 rwhp on a near stock motor is quite impressive. Do honestly have ANY clue what you are talking about? Because you don't. Quote Link to comment Share on other sites More sharing options...
JoroCorona Posted March 9, 2005 Report Share Posted March 9, 2005 If you cryo treat the crank it makes it stronger, allowing it to withstand more roational force. Port and polish to fee up the power band abit. Larger intake and exhaust valse for the same reason. Balance the crank, pullies, shit almost everything that rotates to reduce rotational force. This would allow it to rev higher and make more top end power. I know what I'm talking about. Thanks. The 4g63 is an engine, that in my personal opinion is too small. The LS1 is an engine that still implements push rods. I dont like push rod setups, never hand, more then likely never will. The 2jz is an AWSOME engine. 3.0L of twin turbocharged madness. And with minor modification the thing can put down excessive amounts of power. Maybe 1000 hp was abit of an exageration, but 500-600 hp with stock internals and beefier turbos is quite easy. Quote Link to comment Share on other sites More sharing options...
RacerX Posted March 9, 2005 Report Share Posted March 9, 2005 The only good reason for doing a short-stroke 3400 using a 2.8 crank would be to get maximum power from a displacement limit imposed by rules, hence the 302 in the original Z28. Smaller displacement means revving higher to get horsepower. Why do that if you don't have to. Quote Link to comment Share on other sites More sharing options...
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